大线能量焊接船板钢DH36凝固组织模拟  

Simulation study on solidification microstructure of DH36 ship plate steel with large line energy welding

作　　者：陈伟 屈海珍 李耀 孙风杰 杨改彦 朱立光 CHEN Wei;QU Haizhen;LI Yao;SUN Fengjie;YANG Gaiyan;ZHU Liguang(College of Metallurgy and Energy,North China University of Science and Technology University,Tangshan 063210,Hebei,China;Hebei Key Laboratory of Modern Metallurgical Technology,High Quality Steel Continuous Casting Technology Innovation Center,Tangshan 063009,Hebei,China;College of Materials Science and Engineering,Hebei University of Science and Technology,Shijiazhuang 050091,Hebei,China)

机构地区：[1]华北理工大学冶金与能源学院,河北唐山063210 [2]河北省现代冶金技术重点实验室,高品质钢连铸工程技术创新中心,河北唐山063009 [3]河北科技大学材料科学与工程学院,河北石家庄050091

出　　处：《连铸》2024年第4期21-29,共9页Continuous Casting

基　　金：国家自然科学基金会-区域创新发展联合基金重点资助项目(U21A20114);河北省自然科学基金资助项目(E2020209036)。

摘　　要：为提高大线能量焊接用钢母材的强韧性,基于氧化物冶金技术将微合金化应用于船板钢DH36的开发,探究微合金化对铸坯凝固组织改善的机理及工艺优化措施。通过建立凝固传热及组织数学模型,研究微合金元素与工艺参数对凝固组织细化的影响,利用真空感应炉冶炼试验钢并使用金相显微镜观察试验钢显微组织验证模拟结果。研究结果表明,Mo质量分数为0.040%~0.050%细化效果明显;Nb质量分数从0.030%增加到0.040%过程,凝固组织细化效果较好;Mg质量分数在0.002%~0.003%内增加细化效果明显;V含量增加对凝固组织的影响较小;Ti质量分数在0.015%~0.016%范围更有利于晶粒细化。过热度适当减小有利于组织细化,低拉速更有利于铸坯质量提高。在生产2 400 mm×400 mm断面船板钢DH36铸坯时,为获得优良的钢液凝固组织及细化晶粒,根据本研究应采用的最佳工艺参数为:拉速为0.58~0.60 m/min、过热度为25℃、Mo质量分数为0.050%、Nb质量分数为0.040%、Mg质量分数为0.003 0%、V质量分数为0.003 5%、Ti质量分数为0.015%。结果显示,此工艺条件下凝固组织的等轴晶区域较常规合金含量铸坯提高11个百分点,优化率为35%,晶粒细化效果显著。在试验和计算分析基础上,提出的改善铸坯母材性能的微合金添加含量范围及工艺参数优化措施,可为大线能量焊接船板钢连铸过程工艺优化提供可靠的理论指导。In order to improve the strength and toughness of steel base metal for large line energy welding,microal-loying was applied to the development of ship plate steel DH36 based on oxide metallurgy technology,and the mech-anism and process optimization measures of microalloying on the solidification structure of casting slab were investi-gated.The effect of microalloying elements and process parameters on solidification microstructure refinement was studied by establishing the mathematical model of solidification heat transfer and microstructure.The experimental steel was smelted by vacuum induction furnace and the simulation results were verified by metallographic micro-scope.The results show that the thinning effect is obvious when Mo content(mass fraction)is 0.040%-0.050%.When the content of Nb increases from 0.030%to 0.040%,the thinning effect of solidification structure is better.The thinning effect is obvious when the Mg content increases within 0.002%-0.003%.The increasing of V content has little effect on the solidification structure.Ti content in the range of 0.015%-0.016%is more conducive to grain refinement.The proper reduction of superheat is beneficial to microstructure refinement,and the low casting speed is more conducive to the improvement of casting quality.In the production of 2400 mm X 400 mm section ship plate steel DH36 casting slab,in order to obtain excellent liquid steel solidification structure and fine grain,the best process parameters should be adopted according to this study,casting speed 0.58 m/min-0.60 m/min,superheat of 25 C,Mo content 0.050%,Nb content 0.040%,Mg content 0.003%,V content 0.0035%,Ti content 0.015%.The results show that the equiaxed crystal region of the solidification structure is ll percent point higher than that of the conventional alloy content casting slab,and the optimization rate is 35%.On the basis of experiment and calculation analysis,the content range of microalloy and the optimization measures of process parameters for improving the properties of the base meta

关 键 词：大线能量焊接船板钢 微合金化 凝固组织细化 优化措施 DH36 

分 类 号：TF76[冶金工程—钢铁冶金] TF777